Numerous patents have described the problems and hazards in intra-ocular lens implants, and have proposed numerous and varied artifical lens structures for this purpose. Examples of these prior art patents are the following:
______________________________________ Knight et al 4,170,661 1979 Knight et al 4,170,043 1979 Fedorov et al 3,673,616 1972 Flom 3,866,249 1975 Otter 3,906,551 1975 Potthast 3,913,148 1975 Krasnov 3,922,728 1975 Richards et al 3,925,825 1975 Poler 4,073,014 1978 Poler 4,080,709 1978 Poler 4,118,808 1978 Anis 4,166,293 1979 Schlegel 4,172,297 1979 Welsh 4,173,798 1979 Kelman 4,174,543 1979 Kelman 4,174,543 1979 Kuppinger et al 4,177,526 1979 ______________________________________
The delicacy of the various eye tissues is easily understood, but the merest touch of the tip of a surgical needle or other surgical instrument on the one-cell layer of the endothelial lining on the posterior face of the cornea is likely to tear some of the cells away from the corneal surface, permanently damaging the eye. The risk of such injury during intra-ocular lens implantation accounts for much of the criticism leveled by consumer advocates and lobbyists against lens implantation surgery. The serious risk of permanent damage to the corneal endothelium, and one particular proposal for minimizing such damage, are described in Knight et al U.S. Pat. No. 4,170,661, in the background paragraphs of that patent. A number of surgical instruments have been proposed to minimize such damage and aid the opthalmic surgeon in lens implantation, in such patents as:
______________________________________ Poler 4,122,556 1978 Clark 4,198,980 1980 Hager et al 4,190,049 1980 ______________________________________